• Higher quality products • Higher productivity • Improved utilisation of people and resources (equipment, space, etc.) • Processes that are more responsive to customers
but tend to be wasteful and inefficient. • One-piece flow is a smarter (but harder) alternative: • With one-piece flow, no one produces anything until it is needed by the next person or step in the process. • I.e. there is zero spare inventory in the system, so a problem anywhere can stop the whole production line.
it: • surfaces problems so that they can be fixed and prevented; • minimises feedback time from downstream processes; • empowers workers to stop production when a defect is encountered, in order to fix it and prevent repeats. • Thus teams can learn how to eliminate defects and wasteful activities (muda).
• Cycle times of different processes may vary significantly. • Demand may be uneven. • There may be natural variation in the cycle times of a single process. • Pull systems allow small inventory buffers to smooth the flow of work through the system.
downstream processes which operate at different rates aren’t starved of inventory; • minimizes inventory in supply chain; • blocks production if a defect or delay occurs downstream.
make defects visible; • require quality issues to be resolved and defects to be prevented; • encourage waste reduction (defects a type of muda). • Moreover, TTW encourages reflection, learning and continuous improvement (5 Why's, etc.) – a requisite to achieve zero defects.
include: • failure to create the right culture and discipline; • failure to empower teams to deal with problems; • confusion or panic at early 'costs' when problems surface.
clear flow of work and inventory • Study whole system (incl. queues and inventory) from idea to customer • Focus on throughput rather than utilisation • Avoid hand-offs
reflection and root-cause analysis (e.g. 5 Why's) • Teach and maintain the discipline of continuous improvement • Help teams take ownership of problems and defects
to earlier include: • Minimise inventory and WIP • Reduce WIP limits to surface problems • NB these are refuted as absolute truths by Donald Reinertsen.